I'm sure everyone that has done a kit build has fretted over drilling the holes for your front and rear trunnions. Drilling in the wrong location simply sucks. I personally have implemented the masking tape and pencil method in the past. While in one of my customers shops the other day, I found a better way. The answer is a thin piece of lexan. Thin lexan is easily cut with a utility knife, is quite easy to work, and is very durable. Simply lay a piece against your trunnion, and cut it to fit. With it held firmly in place. Drill out the holes lined up with the rivet holes in your trunnion. After drilling, line it up on your receiver to mark the correct location to drill your trunnion holes. My description after a few beers probably sucks, so if I'm unclear, let me know, and I'll take some pictures during this latest build. Hope this is of help.